Door knob



FIG. 1 is a side elevational view of a door knob showing my new design,the opposite side is a mirror image;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a back elevational view thereof; and,

FIG. 4 is a top plan view thereof, the door knob being hollow and havinga through passage, the undisclosed bottom is not part of the claimeddesign.

I claim the ornamental design for a door knob, as shown and described.